The present invention relates to a screwdriver with insulated shaft and polygonal head which pass through the handle of the screwdriver used to release screws, bolts, etc.
A conventional screwdriver comprises a shaft with one end engaging with the lower end of a handle. The other end of the shaft forming a phillips blade or a flat blade. Such screwdriver can not be driven by a wrench for applying an axial pressure or torque. Korkowski proposed in U.S. Pat. No. 4,541,314 a power driven hand tool which can mate with and be driven by a ratchet mechanism. However, such tool would be easily cracked at the handle-shaft engaging point if used in conjunction with a hammer as a chisel-device. In further developement, the shaft was designed to pass through the handle. In this case, if a screw desired to be loosened came in contacts with a live wire, an operator using such a screwdriver to loosen the screw would get a shock.
It is the purpose of the present invention, therefore, to mitigate and/or obviate the above-mentioned drawbacks in the manner set forth in the detailed description of the preferred embodiment.